Display device and manufacturing method thereof

ABSTRACT

A display device includes a substrate, a switching transistor and a driving transistor positioned on the substrate, a first electrode connected to the driving transistor, a second electrode positioned on the first electrode, and a pixel definition layer positioned between the first electrode and the second electrode, where the pixel definition layer includes a first portion, and a second portion having a thickness less than that of the first portion, where a pixel opening defined in the pixel definition layer is enclosed by the first portion, and the second portion overlaps the first electrode and the second electrode.

This application is a divisional application of U.S. patent applicationSer. No. 15/870,073, filed on Jan. 12, 2018, which claims priority toKorean Patent Application No. 10-2017-0067033, filed on May 30, 2017,and all the benefits accruing therefrom under 35 U.S.C. § 119, thecontent of which in its entirety is herein incorporated by reference.

BACKGROUND 1. Field

Exemplary embodiments of the invention relate to a display device and amanufacturing method thereof, and in detail, relate to a display deviceand a manufacturing method for improving element reliability.

2. Description of the Related Art

An organic light emitting diode display generally includes twoelectrodes and an organic emission layer interposed therebetween.Electrons injected from one electrode of the two electrodes and holesinjected from the other electrode of the two electrodes are combined inthe organic emission layer to generate excitons. The generated excitonsare changed to a ground state from an excited state, releasing energy toemit light.

The organic light emitting diode display includes a plurality of pixelsincluding an organic light emitting diode as a self-emissive element,and a plurality of transistors for driving the organic light emittingdiode and at least one capacitor are formed in each pixel. The pluralityof transistors generally includes a switching transistor and a drivingtransistor.

SUMMARY

In a process of elongating a number of pixels for increasing resolutionof an organic light emitting diode display, an aperture ratio maydecrease, a current density may increase, and a driving voltage mayincrease. Accordingly, there are problems that stains are generated andreliability of elements such as a thin film transistor decreases.

Exemplary embodiments provide a display device and a manufacturingmethod for improving element reliability.

A display device according to an exemplary embodiment includes asubstrate, a switching transistor and a driving transistor positioned onthe substrate, a first electrode connected to the driving transistor, asecond electrode positioned on the first electrode, and a pixeldefinition layer positioned between the first electrode and the secondelectrode, and including a first portion, and a second portion having athickness less than that of the first portion, where a pixel openingdefined in the pixel definition layer is enclosed by the first portion,and the second portion overlaps the first electrode and the secondelectrode.

In an exemplary embodiment, the first electrode and the second electrodemay overlap the first portion, the second portion, and the pixel openingof the pixel definition layer.

In an exemplary embodiment, a distance between a first portion of thefirst electrode overlapping the first portion of the pixel definitionlayer and a first portion of the second electrode may be greater than adistance between a second portion of the first electrode overlapping thesecond portion of the pixel definition layer and a second portion of thesecond electrode.

In an exemplary embodiment, a distance between a third portion of thefirst electrode overlapping the pixel opening of the pixel definitionlayer and a third portion of the second electrode may be less than thedistance between the second portion of the first electrode overlappingthe second portion of the pixel definition layer and the second portionof the second electrode.

In an exemplary embodiment, the first portion of the pixel definitionlayer may be positioned between the pixel opening and the secondportion.

In an exemplary embodiment, an organic emission layer positioned betweenthe first electrode and the second electrode may be further included.

In an exemplary embodiment, the organic emission layer may be positionedbetween the pixel definition layer and the second electrode.

In an exemplary embodiment, the second portion of the pixel definitionlayer may overlap the organic emission layer.

In an exemplary embodiment, the first electrode, the second electrode,and the organic emission layer overlap the first portion, the secondportion, and the pixel opening of the pixel definition layer.

In an exemplary embodiment, the second portion of the pixel definitionlayer may not overlap the organic emission layer.

In an exemplary embodiment, the first electrode and the second electrodemay overlap the first portion, the second portion, and the pixel openingof the pixel definition layer, and the organic emission layer mayoverlap the pixel opening of the pixel definition layer.

In an exemplary embodiment, the first portion of the pixel definitionlayer may be positioned between the pixel opening and the secondportion, and may be positioned between a plurality of second portionsadjacent to each other.

In an exemplary embodiment, the first portion of the pixel definitionlayer may not overlap the organic emission layer between the pluralityof second portions adjacent to each other.

In an exemplary embodiment, the organic emission layer may include afirst organic emission layer emitting a first color and a second organicemission layer emitting a second color, and the first organic emissionlayer and the second organic emission layer may not overlap each other.

In an exemplary embodiment, a display device according to an exemplaryembodiment includes a substrate, a first electrode positioned on thesubstrate, a pixel definition layer positioned on the substrate and thefirst electrode and including a first portion, and a second portionhaving a thickness less than that of the first portion, an organicemission layer positioned on the first electrode, and a second electrodepositioned on the organic emission layer, where a pixel opening definedin the pixel definition layer is enclosed by the first portion, and thesecond portion overlaps the first electrode and the second electrode.

In an exemplary embodiment, the first electrode and the second electrodemay overlap the first portion, the second portion, and the pixel openingof the pixel definition layer.

In an exemplary embodiment, a distance between a first portion of thefirst electrode overlapping a first portion of the pixel definitionlayer and a first portion of the second electrode may be greater than adistance between a second portion of the first electrode overlapping thesecond portion of the pixel definition layer and a second portion of thesecond electrode.

In an exemplary embodiment, the first portion of the pixel definitionlayer may be positioned between the pixel opening and the secondportion.

In an exemplary embodiment, the second portion of the pixel definitionlayer may further overlap the organic emission layer.

A manufacturing method of a display device according to an exemplaryembodiment includes forming a first electrode on a substrate, forming anorganic material layer on the substrate and the first electrode,patterning the organic material layer to form a pixel definition layerincluding a first portion, a second portion, and a pixel opening,forming an organic emission layer on the first electrode, and forming asecond electrode on the organic emission layer, where the second portionhas a thickness less than that of the first portion, and the secondportion overlaps the first electrode and the second electrode.

In an exemplary embodiment, at least one of a slit mask and a half-tonemask may be used in the step of patterning the organic material layer.

In an exemplary embodiment, the pixel opening may be enclosed by thefirst portion.

In an exemplary embodiment, the first electrode and the second electrodemay overlap the first portion, the second portion, and the pixel openingof the pixel definition layer.

In an exemplary embodiment, a distance between a first portion of thefirst electrode overlapping the first portion of the pixel definitionlayer and a first portion of the second electrode may be greater than adistance between a second portion of the first electrode overlapping thesecond portion of the pixel definition layer and a second portion of thesecond electrode.

In an exemplary embodiment, the first portion of the pixel definitionlayer may be positioned between the pixel opening and the secondportion.

In an exemplary embodiment, the second portion of the pixel definitionlayer may further overlap the organic emission layer.

In an exemplary embodiment, the display device and the manufacturingmethod thereof according to the exemplary embodiments may improveelement reliability.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other exemplary embodiments, advantages and features ofthis disclosure will become more apparent by describing in furtherdetail exemplary embodiments thereof with reference to the accompanyingdrawings, in which:

FIG. 1 is a plan view of an exemplary embodiment of a display device;

FIG. 2 is a cross-sectional view of the display device of FIG. 1 takenalong line II-II;

FIGS. 3 and 4 are process cross-sectional views showing an exemplaryembodiment of a manufacturing method of a display device;

FIG. 5 is a plan view of an exemplary embodiment of a display device;

FIG. 6 is a cross-sectional view of the display device of FIG. 5 takenalong line VI-VI;

FIG. 7 is a plan view of an exemplary embodiment of a display device;

FIG. 8 is a cross-sectional view of the display device of FIG. 7 takenalong line VIII-VIII;

FIGS. 9 and 10 are cross-sectional views of an exemplary embodiment of adisplay device;

FIG. 11 is a plan view of an exemplary embodiment of a display device;

FIG. 12 is a cross-sectional view of the display device of FIG. 11 takenalong line XII-XII;

FIG. 13 is an equivalent circuit diagram of an exemplary embodiment ofone pixel of a display device;

FIG. 14 is a schematic plan view of an exemplary embodiment of atransistor and a capacitor of a red pixel, a green pixel, and a bluepixel of a display device;

FIG. 15 is a detailed plan view of one pixel of FIG. 14;

FIG. 16 is a cross-sectional view of the display device of FIG. 15 takenalong line XVI-XVI;

FIG. 17 a cross-sectional view of the display device of FIG. 15 takenalong lines XVII-XVII and XVII′-XVII′; and

FIG. 18 is a plan view of an exemplary embodiment of a display device.

DETAILED DESCRIPTION

The invention will be described more fully hereinafter with reference tothe accompanying drawings, in which exemplary embodiments of theinvention are shown. As those skilled in the art would realize, thedescribed embodiments may be modified in various different ways, allwithout departing from the spirit or scope of the invention.

In order to clearly explain the invention, portions that are notdirectly related to the invention are omitted, and the same referencenumerals are attached to the same or similar constituent elementsthroughout the entire specification.

In addition, the size and thickness of each configuration shown in thedrawings are arbitrarily shown for better understanding and ease ofdescription, but the invention is not limited thereto. In the drawings,the thickness of layers, films, panels, regions, etc., are exaggeratedfor clarity. In the drawings, for better understanding and ease ofdescription, the thicknesses of some layers and areas are exaggerated.

It will be understood that when an element such as a layer, film,region, or substrate is referred to as being “on” another element, itcan be directly on the other element or intervening elements may also bepresent. In contrast, when an element is referred to as being “directlyon” another element, there are no intervening elements present. Further,in the specification, the word “on” or “above” means positioned on orbelow the object portion, and does not necessarily mean positioned onthe upper side of the object portion based on a gravitational direction.

In addition, unless explicitly described to the contrary, the word“comprise” and variations such as “comprises” or “comprising” will beunderstood to imply the inclusion of stated elements but not theexclusion of any other elements.

Further, in the specification, the phrase “in a plan view” means viewingthe object portion from the top, and the phrase “on a cross-section”means viewing a cross-section of which the object portion is verticallycut from the side.

It will be understood that, although the terms “first,” “second,”“third” etc. may be used herein to describe various elements,components, regions, layers and/or sections, these elements, components,regions, layers and/or sections should not be limited by these terms.These terms are only used to distinguish one element, component, region,layer or section from another element, component, region, layer orsection. Thus, “a first element,” “component,” “region,” “layer” or“section” discussed below could be termed a second element, component,region, layer or section without departing from the teachings herein.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” “an,” and “the” are intended to include the pluralforms, including “at least one,” unless the content clearly indicatesotherwise. “Or” means “and/or.” As used herein, the term “and/or”includes any and all combinations of one or more of the associatedlisted items.

Furthermore, relative terms, such as “lower” or “bottom” and “upper” or“top,” may be used herein to describe one element's relationship toanother element as illustrated in the Figures. It will be understoodthat relative terms are intended to encompass different orientations ofthe device in addition to the orientation depicted in the Figures. In anexemplary embodiment, when the device in one of the figures is turnedover, elements described as being on the “lower” side of other elementswould then be oriented on “upper” sides of the other elements. Theexemplary term “lower,” can therefore, encompasses both an orientationof “lower” and “upper,” depending on the particular orientation of thefigure. Similarly, when the device in one of the figures is turned over,elements described as “below” or “beneath” other elements would then beoriented “above” the other elements. The exemplary terms “below” or“beneath” can, therefore, encompass both an orientation of above andbelow.

“About” or “approximately” as used herein is inclusive of the statedvalue and means within an acceptable range of deviation for theparticular value as determined by one of ordinary skill in the art,considering the measurement in question and the error associated withmeasurement of the particular quantity (i.e., the limitations of themeasurement system). For example, “about” can mean within one or morestandard deviations, or within ±30%, 20%, 10%, 5% of the stated value.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and theinvention, and will not be interpreted in an idealized or overly formalsense unless expressly so defined herein.

Exemplary embodiments are described herein with reference to crosssection illustrations that are schematic illustrations of idealizedembodiments. As such, variations from the shapes of the illustrations asa result, for example, of manufacturing techniques and/or tolerances,are to be expected. Thus, embodiments described herein should not beconstrued as limited to the particular shapes of regions as illustratedherein but are to include deviations in shapes that result, for example,from manufacturing. In an exemplary embodiment, a region illustrated ordescribed as flat may, typically, have rough and/or nonlinear features.Moreover, sharp angles that are illustrated may be rounded. Thus, theregions illustrated in the figures are schematic in nature and theirshapes are not intended to illustrate the precise shape of a region andare not intended to limit the scope of the claims.

First, the display device according to an exemplary embodiment will bedescribed with reference to FIGS. 1 and 2.

FIG. 1 is a plan view of a display device according to an exemplaryembodiment, and FIG. 2 is a cross-sectional view of the display deviceof FIG. 1 taken along line II-II.

As shown in FIGS. 1 and 2, the display device according to an exemplaryembodiment includes a substrate 110, a first electrode 191 positioned onthe substrate 110, and a second electrode 270 positioned on the firstelectrode 191. A pixel definition layer 350 is positioned between thefirst electrode 191 and the second electrode 270.

In an exemplary embodiment, the substrate 110 may be an insulatingsubstrate including glass, quartz, ceramic, plastic, etc., or a metalsubstrate including stainless steel and the like. The substrate 110 maybe flexible, stretchable, foldable, bendable, or rollable. As thesubstrate 110 may be flexible, stretchable, foldable, bendable, orrollable, the display device may also be flexible, stretchable,foldable, bendable, or rollable.

A buffer layer 120 may be positioned on the substrate 110. In anexemplary embodiment, the buffer layer 120 may be provided as a singlelayer of a silicon nitride (SiNx) or as a multilayer in which a siliconnitride (SiNx) and a silicon oxide (SiOx) are stacked, for example. Thebuffer layer 120 serves to flatten a surface while preventingundesirable materials such as impurities or moisture from permeating. Inanother exemplary embodiment, the buffer layer 120 may be omitted whennecessary. The buffer layer 120 may be provided to cover an entire uppersurface of the substrate 110.

A semiconductor 135 is positioned on the buffer layer 120. Thesemiconductor 135 may include a polycrystalline semiconductor materialor an oxide semiconductor material. In addition, the semiconductor 135includes a channel 131 in which impurities are not doped, and contactdoping regions 132 and 133 that are positioned at opposite sides of thechannel 131 and in which impurities are doped. The contact dopingregions 132 and 133 include a source region 132 and a drain region 133.The impurities vary depending on a kind of the thin film transistor(“TFT”).

A gate insulating layer 140 is positioned on the semiconductor 135. Inan exemplary embodiment, the gate insulating layer 140 may include theinorganic insulating material such as a silicon nitride (SiNx) or asilicon oxide (SiOx).

A gate electrode 125 is positioned on the gate insulating layer 140. Inthis case, the gate electrode 125 overlaps at least a part of thesemiconductor 135, and particularly, overlaps the channel 131. Here, theoverlapping means to be overlapped in a vertical direction in across-sectional view.

An interlayer insulating layer 160 is positioned on the gate electrode125 and the gate insulating layer 140. The interlayer insulating layer160 may include the inorganic insulating material or the organicinsulating material.

Contact holes 162 and 164 overlapping at least part of the semiconductor135 are defined in the gate insulating layer 140 and the interlayerinsulating layer 160. The contact holes 162 and 164 respectively exposethe contact doping regions 132 and 133 of the semiconductor 135.

A source electrode 173 and a drain electrode 175 are positioned on theinterlayer insulating layer 160. Also, the source electrode 173 and thedrain electrode 175 are connected to the source region 132 and the drainregion 133 of the semiconductor 135 through the contact holes 162 and164, respectively.

As described above, the semiconductor 135, the gate electrode 125, thesource electrode 173, and the drain electrode 175 configure one TFT. Astructure of the TFT is not limited to the aforementioned example, andmay be modified to a variety of disclosed structures that can be easilyimplemented by those skilled in the art. The organic light emittingdiode display may include a switching transistor and a drivingtransistor, and the aforementioned TFT may be the driving transistor.Although not illustrated, a switching TFT may be provided.

A passivation layer 180 is positioned on the TFT and the interlayerinsulating layer 160. The passivation layer 180 serves to remove andflatten steps, thereby increasing luminous efficiency of the organiclight emitting diode to be disposed thereon. A contact hole 182overlapping at least a part of the drain electrode 175 is defined in thepassivation layer 180.

In an exemplary embodiment, the passivation layer 180 may include atleast one of a polyacrylate resin, an epoxy resin, a phenolic resin, apolyamide resin, a polyimide resin, an unsaturated polyester resin, apolyphenylene resin, a polyphenylene sulfide resin, and benzocyclobutene(“BCB”), for example.

The first electrode 191 is positioned on the passivation layer 180. Inan exemplary embodiment, the first electrode 191 may include atransparent conductive material such as indium tin oxide (“ITO”), indiumzinc oxide (“IZO”), zinc oxide (ZnO), indium oxide (In2O3), etc., or areflective metal such as lithium (Li), calcium (Ca), lithiumfluoride/calcium (LiF/Ca), lithium fluoride/aluminum (LiF/Al), aluminum(Al), silver (Ag), magnesium (Mg), gold (Au), etc. The first electrode191 is electrically connected to the drain electrode 175 of the TFT viathe contact hole 182 defined in the passivation layer 180, and becomesthe anode of the organic light emitting diode.

Although not illustrated, the first electrode 191 may include first andsecond transparent electrodes including a transparent conductivematerial, and a semi-transmissive layer positioned between the first andsecond transparent electrodes to form a microcavity together with thesecond electrode 270. That is, the first electrode 191 may be providedas a multilayer including a layer including the transparent conductivematerial and a layer including a reflective metal material.

The pixel definition layer 350 is positioned on the passivation layer180 and the first electrode 191. In an exemplary embodiment, the pixeldefining layer 350 may include a resin such as a polyacrylate resin anda polyimide resin, or a silica-based inorganic material, for example.The pixel definition layer 350 includes a first portion 350 a and asecond portion 350 b, and a pixel opening 351 is defined in the pixeldefinition layer 350.

The first portion 350 a of the pixel definition layer 350 has apredetermined thickness and encloses the pixel opening 351. The firstportion 350 a may be positioned between the pixel opening 351 and thesecond portion 350 b. In FIG. 1, a boundary of the first portion 350 aand the second portion 350 b of the pixel definition layer 350 isindicated by a dotted line.

The second portion 350 b of the pixel definition layer 350 is adjacentto the first portion 350 a. A thickness t2 of the second portion 350 bof the pixel definition layer 350 is less than a thickness t1 of thefirst portion 350 a. In an exemplary embodiment, the thickness t1 of thefirst portion 350 a of the pixel definition layer 350 may be about 1.2micrometers (μm), and the thickness t2 of the second portion 350 b ofthe pixel definition layer 350 may be about 0.3 μm, for example.

The pixel opening 351 of the pixel definition layer 350 means an openingregion defined in the pixel definition layer 350, and may overlap acenter of the first electrode 191. Accordingly, the pixel opening 351exposes at least part of the upper surface of the first electrode 191.

An organic emission layer 370 is positioned on the first electrode 191.The organic emission layer 370 may include at least one of an emissionlayer, a hole-injection layer (“HIL”), a hole-transporting layer(“HTL”), an electron-transporting layer (“ETL”), and anelectron-injection layer (“EIL”).

The organic emission layer 370 may include a red organic emission layer370R emitting red light, a green organic emission layer 370G emittinggreen light, and a blue organic emission layer 370B emitting blue light.The organic emission layer 370 may be made with an approximate diamondshape and may be disposed as a pentile type. In an exemplary embodiment,the red organic emission layer 370R and the green organic emission layer370G may be alternately disposed in a diagonal direction, and the blueorganic emission layer 370B and the green organic emission layer 370Gmay be alternately disposed in the diagonal direction, for example. Thered organic emission layer 370R, the green organic emission layer 370G,and the blue organic emission layer 370B are positioned at differentpixels from one another, thereby realizing a color image by combinationsthereof.

In an alternative exemplary embodiment, the organic emission layer 370may have a structure in which the red organic emission layer 370R, thegreen organic emission layer 370G, and the blue organic emission layer370B are respectively stacked on corresponding pixels. In this case, acolor image may be implemented by forming a red filter, a green filter,or a blue filter for each pixel. In another exemplary embodiment, byforming a white organic emission layer for emitting white light at eachpixel and by forming a red filter, a green filter, and a blue filter foreach pixel, it is possible to implement a color image. When the colorimage is implemented by using the white organic emission layer and thecolor filter, a deposition mask for respectively depositing the redorganic emission layer 370R, the green organic emission layer 370G, andthe blue organic emission layer 370B on each corresponding pixel, thatis, on the red pixel, the green pixel, and the blue pixel, is notdesired.

The white organic emission layer described in another example may beprovided as a single organic emission layer, and may be provided as aplurality of organic emission layers stacked so that the white light maybe emitted. In an exemplary embodiment, a structure for emitting whitelight by combining at least one yellow organic emission layer with atleast one blue organic emission layer 370B, a structure for emittingwhite light by combining at least one cyan organic emission layer withat least one red organic emission layer 370R, and a structure foremitting white light by combining at least one magenta organic emissionlayer with at least one green organic emission layer 370G may beincluded, for example.

The second electrode 270 is positioned on the organic emission layer 370and the pixel definition layer 350. In an exemplary embodiment, thesecond electrode 270 may include a transparent conductive material suchas ITO, IZO, zinc oxide (ZnO), indium oxide (In2O3), etc., or areflective metal such as lithium (Li), calcium (Ca), lithiumfluoride/calcium (LiF/Ca), lithium fluoride/aluminum (LiF/Al), aluminum(Al), silver (Ag), magnesium (Mg), gold (Au), etc. The second electrode270 serves as a cathode of the organic light emitting diode, forexample.

The first electrode 191 includes a first portion 191 a overlapping thefirst portion 350 a of the pixel definition layer 350, a second portion191 b overlapping the second portion 350 b of the pixel definition layer350, and a third portion 191 c overlapping the pixel opening 351 of thepixel definition layer 350. In this case, the overlapping means to beoverlapped in the vertical direction in the cross-sectional view.

The second electrode 270 includes a first portion 270 a overlapping thefirst portion 350 a of the pixel definition layer 350, a second portion270 b overlapping the second portion 350 b of the pixel definition layer350, and a third portion 270 c overlapping the pixel opening 351 of thepixel definition layer 350.

Accordingly, the first electrode 191 and the second electrode 270overlap the first portion 350 a, the second portion 350 b, and the pixelopening 351 of the pixel definition layer 350.

The third portion 191 c of the first electrode 191 and the third portion270 c of the second electrode 270 positioned in the pixel opening 351are in contact with the organic emission layer 370. The third portion191 c of the first electrode 191 may in contact with the lower surfaceof the organic emission layer 370, and the third portion 270 c of thesecond electrode 270 may be in contact with the upper surface of theorganic emission layer 370. The third portion 191 c of the firstelectrode 191 and the second electrode 270 form the organic lightemitting diode OLED along with the organic emission layer 370. Theorganic light emitting diode OLED positioned in the pixel opening 351emits the light when the TFT is in the on-state, and the pixel opening351 defines the emission region.

The first portion 350 a of the pixel definition layer 350 is positionedbetween the first portion 191 a of the first electrode 191 and the firstportion 270 a of the second electrode 270. The organic emission layer370 may be further positioned between the first portion 270 a of thesecond electrode 270 and the first portion 350 a of the pixel definitionlayer 350.

The second portion 350 b of the pixel definition layer 350 is positionedbetween the second portion 191 b of the first electrode 191 and thesecond portion 270 b of the second electrode 270. The organic emissionlayer 370 may be further positioned between the second portion 270 b ofthe second electrode 270 and the second portion 350 b of the pixeldefinition layer 350. That is, the second portion 350 b of the pixeldefinition layer 350 overlaps the organic emission layer 370.

Since the thickness t2 of the second portion 350 b of the pixeldefinition layer 350 is less than the thickness t1 of the first portion350 a of the pixel definition layer 350, a distance between the secondportion 191 b of the first electrode 191 and the second portion 270 b ofthe second electrode 270 is less than a distance between the firstportion 191 a of the first electrode 191 and the first portion 270 a ofthe second electrode 270. That is, the distance between the firstportion 191 a of the first electrode 191 and the first portion 270 a ofthe second electrode 270 is greater than the distance of the secondportion 191 b of the first electrode 191 and the second portion 270 b ofthe second electrode 270.

In general, the thickness of the pixel definition layer 350 may be madeto be substantially constant. A predetermined thickness difference maybe generated between the portion of the pixel definition layer 350overlapping the first electrode 191 and the portion of the pixeldefinition layer 350 that does not overlap the first electrode 191. Inan exemplary embodiment, the difference in the thickness of the firstelectrode 191 may be generated, for example. In the illustratedexemplary embodiment, the difference between the thickness of the firstportion 350 a of the pixel definition layer 350 and the thickness of thesecond portion 350 b may be larger than the thickness of the firstelectrode 191.

Also, the first electrode 191 does not substantially overlap the pixeldefinition layer 350 except for the pixel opening 351. Most of the firstelectrode 191 is positioned in the pixel opening 351, and only a part ofthe edge region of the first electrode 191 overlaps the pixel definitionlayer 350. In the illustrated exemplary embodiment, the first electrode191 is positioned in the pixel opening 351 and also overlaps most of thepixel definition layer 350 except for the pixel opening 351. The firstelectrode 191 overlaps the first portion 350 a of the pixel definitionlayer 350 adjacent to the pixel opening 351 and also overlaps the secondportion 350 b of the pixel definition layer 350.

As the second portion 350 b of the pixel definition layer 350 having thesmaller thickness than the thickness t1 of the first portion 350 a ofthe pixel definition layer 350 overlaps the first electrode 191 and thesecond electrode 270, the current density may decrease and the drivingvoltage may decrease by additionally obtaining the capacitance, therebyimproving reliability of the element. That is, in the illustratedexemplary embodiment, the area of the first electrode 191 positionedunder the pixel definition layer 350 increases and the thickness of thepixel definition layer 350 positioned between the first electrode 191and the second electrode 270 decreases, thereby additionally obtainingthe capacitance.

It is preferable that the thickness t1 of the first portion 350 a of thepixel definition layer 350 is more than a predetermined thickness. Whenthe thickness of the first portion 350 a decreases to the thicknesslevel of the second portion 350 b, the capacitance may further increase,but boundaries between the plurality of pixels become unclear. In anexemplary embodiment, when the first portion 350 a is less than thepredetermined thickness, the green organic emission layer 370G or theblue organic emission layer 370B may penetrate in the pixel opening 351in which the red organic emission layer 370R is disposed, for example.Accordingly, as the thickness t1 of the first portion 350 a positionedbetween the pixel opening 351 and the second portion 350 b is greaterthan the thickness t2 of the second portion 350 b, color mixture betweenthe adjacent pixels may be prevented.

The distance between the third portion 191 c of the first electrode 191and the third portion 270 c of the second electrode 270 is smaller thanthe distance between the first portion 191 a of the first electrode 191and the first portion 270 a of the second electrode 270. Also, thedistance between the third portion 191 c of the first electrode 191 andthe third portion 270 c of the second electrode 270 is smaller than thedistance between the second portion 191 b of the first electrode 191 andthe second portion 270 b of the second electrode 270.

The first portion 191 a of the first electrode 191 and the first portion270 a of the second electrode 270 overlapping the first portion 350 a ofthe pixel definition layer 350 are not in contact with the organicemission layer 370. The second portion 191 b of the first electrode 191and the second portion 270 b of the second electrode 270 overlapping thesecond portion 350 b of the pixel definition layer 350 are not incontact with the organic emission layer 370. Accordingly, the portionoverlapping the first portion 350 a and the second portion 350 b of thepixel definition layer 350 does not emit the light.

Next, the manufacturing method of the display device according to theillustrated exemplary embodiment will be described with reference toFIGS. 3 and 4.

Particularly, the method of forming the pixel definition layer of thedisplay device according to the illustrated exemplary embodiment will bedescribed.

FIGS. 3 and 4 are process cross-sectional views showing a manufacturingmethod of a display device according to an exemplary embodiment.

As shown in FIG. 3, a semiconductor 135, a gate electrode 125, a sourceelectrode 173, and a drain electrode 175 are sequentially disposed on asubstrate 110 to form a TFT. A passivation layer 180 is disposed on theTFT, and the passivation layer 180 is patterned to define a contact hole182 exposing at least part of the drain electrode 175. A first electrode191 connected with the drain electrode 175 is disposed on thepassivation layer 180.

An organic material layer 500 is disposed on the passivation layer 180and the first electrode 191. A mask 600 is aligned on the organicmaterial layer 500 and an exposure process is performed. In this case,the mask 600 may be a slit mask or a half-tone mask. The mask 600includes a non-transmissive region NR blocking most of light, ahalf-transmissive region HR blocking some of light and allowing theremaining light to be transmitted therethrough, and a transmissiveregion TR allowing most of light to be transmitted therethrough. Whenthe mask 600 is a slit mask, the half-transmissive region HR may beprovided to have a slit shape.

A portion of the organic material layer 500 corresponding to thenon-transmissive region NR of the mask 600 is not substantially exposedto light, a portion of the organic material layer 500 corresponding tothe half-transmissive region HR of the mask 600 is exposed to some oflight, and a portion of the organic material layer 500 corresponding tothe transmissive region TR of the mask 600 is exposed to most of light.

As shown in FIG. 4, the organic material layer 500 is patterned to forma pixel definition layer 350 including a first portion 350 a and asecond portion 350 b having different thicknesses. The first electrode191 is exposed by the portion where the organic material layer 500 isremoved and the portion defines the pixel opening 351 of the pixeldefinition layer 350.

Next, an organic emission layer 370 and a second electrode 270 aresequentially disposed on the first electrode 191 to complete the displaydevice according to the exemplary embodiment shown in FIG. 2.

Next, the display device according to an exemplary embodiment will bedescribed with reference to FIGS. 5 and 6.

The display device according to the exemplary embodiment shown in FIGS.5 and 6 is substantially the same as the display device according to anexemplary embodiment shown in FIGS. 1 and 2 such that the descriptionthereof is omitted. In the illustrated exemplary embodiment, a planeshape of the first electrode and the organic emission layer in a planview is different from the previous exemplary embodiment, and this isdescribed in detail.

FIG. 5 is a plan view of a display device according to an exemplaryembodiment, and FIG. 6 is a cross-sectional view of the display deviceof FIG. 5 taken along line VI-VI.

Like the previous exemplary embodiment, the display device according toan exemplary embodiment includes a first electrode 191, a secondelectrode 270 positioned on the first electrode 191, and a pixeldefinition layer 350 positioned between the first electrode 191 and thesecond electrode 270.

In the previous exemplary embodiment, the first electrode 191 is made asa polygon having ten or more sides in a plan view, but the firstelectrode 191 may have a shape similar to a rectangle in the illustratedexemplary embodiment. That is, in the illustrated exemplary embodiment,the shape of the first electrode 191 is simpler than the shape of thefirst electrode 191 in the previous exemplary embodiment, and a sizethereof is further increased.

In the previous exemplary embodiment, the organic emission layer 370 isprovided with the diamond shape in a plan view, but the organic emissionlayer 370 is provided as a rectangle in a plan view in the illustratedexemplary embodiment.

The shape of the first electrode 191 and the organic emission layer 370is not limited thereto and may be variously changed. In an exemplaryembodiment, the first electrode 191 and the organic emission layer 370may be provided as the polygon having a plurality of sides, and somesides may be replaced with a curved line, for example.

In the display device according to an exemplary embodiment, the pixelsare disposed as the pentile type in which capacitance of the red pixeland the blue pixel is desired, but additional capacitance may not bedesired in the green pixel. Accordingly, the area expansion of the firstelectrode 191 is desired in the red pixel and the blue pixel, and thefirst electrode 191 may overlap the pixel definition layer 350 exceptfor the pixel opening 351 like a general structure in the green pixel.Also, a thickness reduction of the partial region of the pixeldefinition layer may be desired in the red pixel and the blue pixel, andthe thickness of the pixel definition layer may be provided to beconstant in the green pixel.

Next, the display device according to an exemplary embodiment will bedescribed with reference to FIGS. 7 and 8.

The display device according to the exemplary embodiment shown in FIGS.7 and 8 is substantially the same as the display device according to anexemplary embodiment shown in FIGS. 1 and 2 such that the descriptionthereof is omitted. In the illustrated exemplary embodiment, a pointthat the organic emission layer does not overlap the first portion andthe second portion of the pixel definition layer is different from theprevious exemplary embodiment, and this is described in detail.

FIG. 7 is a plan view of a display device according to an exemplaryembodiment, and FIG. 8 is a cross-sectional view of the display deviceof FIG. 7 taken along line VIII-VIII.

As shown in FIGS. 7 and 8, the display device according to an exemplaryembodiment includes the substrate 110, the first electrode 191positioned on the substrate 110, and the second electrode 270 positionedon the first electrode 191. The pixel definition layer 350 is positionedbetween the first electrode 191 and the second electrode 270.

In the previous exemplary embodiment, the organic emission layer 370overlaps the first portion 350 a, the second portion 350 b, and thepixel opening 351 of the pixel definition layer 350, but the organicemission layer 370 overlaps the pixel opening 351 of the pixeldefinition layer 350 in the illustrated exemplary embodiment. In theillustrated exemplary embodiment, the organic emission layer 370 doesnot overlap the first portion 350 a and the second portion 350 b of thepixel definition layer 350. That is, the organic emission layer 370 isonly positioned in the pixel opening 351 of the pixel definition layer350.

Even when the organic emission layer 370 does not overlap the secondportion 350 b of the pixel definition layer 350, the capacitance isgenerated between the second portion 191 b of the first electrode 191and the second portion 270 b of the second electrode 270. Accordingly,in the illustrated exemplary embodiment, as the first electrode 191 andthe second electrode 270 overlap via the second portion 350 b of theorganic emission layer 370, the capacitance may be additionally secured,thereby improving the reliability of the element.

Next, the display device according to an exemplary embodiment will bedescribed with reference to FIGS. 9 and 10.

The display device according to the exemplary embodiment shown in FIGS.9 and 10 is substantially the same as the display device according to anexemplary embodiment shown in FIGS. 1 and 2 such that the descriptionthereof is omitted. In the illustrated exemplary embodiment, a pointthat the thickness of the pixel definition layer is changed is differentfrom the previous exemplary embodiment, and this is described in detail.

FIGS. 9 and 10 are cross-sectional views of a display device accordingto an exemplary embodiment.

As shown in FIG. 9, the second portion 350 b of the pixel definitionlayer 350 of the display device according to the illustrated exemplaryembodiment may be less than the second portion 350 b of the pixeldefinition layer 350 of the display device according to the exemplaryembodiment shown in FIGS. 1 and 2.

As shown in FIG. 10, the second portion 350 b of the pixel definitionlayer 350 of the display device according to the illustrated exemplaryembodiment may be greater than the second portion 350 b of the pixeldefinition layer 350 of the display device according to the exemplaryembodiment shown in FIGS. 1 and 2.

In this way, the thickness of the second portion 350 b of the pixeldefinition layer 350 may be changed within a predetermined range. Whenthe second portion 350 b of the pixel definition layer 350 is very thin,the first electrode 191 and the organic emission layer 370 may be incontact or the first electrode 191 and the second electrode 270 may beshorted. Accordingly, it is preferable that the second portion 350 b ofthe pixel definition layer 350 includes the predetermined thickness ormore. When the second portion 350 b of the pixel definition layer 350 isvery thick, the capacitance may be hardly provided between the firstelectrode 191 and the second electrode 270. Accordingly, it ispreferable that the second portion 350 b of the pixel definition layer350 includes the predetermined thickness or less.

As the second portion 350 b of the pixel definition layer 350 becomesthinner, the capacitance can be further secured. Also, as the area ofthe second portion 191 b of the first electrode 191 overlapping thesecond portion 350 b of the pixel definition layer 350 is expanded, thecapacitance can be further secured.

Next, the display device according to an exemplary embodiment will bedescribed with reference to FIGS. 11 and 12.

The display device according to the exemplary embodiment shown in FIGS.11 and 12 is substantially the same as the display device according toan exemplary embodiment shown in FIGS. 1 and 2 such that the descriptionthereof is omitted. In the illustrated exemplary embodiment, a pointthat the first portion 350 a of the pixel definition layer 350 isfurther positioned between the plurality of second portions 350 badjacent to each other is different from the previous exemplaryembodiment, and this is described in detail.

FIG. 11 is a plan view of a display device according to an exemplaryembodiment, and FIG. 12 is a cross-sectional view of the display deviceof FIG. 11 taken along line XII-XII.

The first portion 350 a of the pixel definition layer 350 is positionedbetween the pixel opening 351 and the second portion 350 b in theprevious exemplary embodiment, but the first portion 350 a of the pixeldefinition layer 350 is positioned between the pixel opening 351 and thesecond portion 350 b and between the plurality of second portions 350 badjacent to each other in the illustrated exemplary embodiment.

The organic emission layer 370 may overlap the second portion 350 b ofthe pixel definition layer 350. Although the organic emission layers 370adjacent to each other are designed to be overlapped with each other,the organic emission layers 370 adjacent to each other may be overlappedwith each other in the process. In an exemplary embodiment, the redorganic emission layer 370R and the blue organic emission layer 370B maybe overlapped with each other, and when the overlapping part ispositioned in the pixel opening 351, the color mixing phenomenon may begenerated, for example. In the illustrated exemplary embodiment, as thefirst portion 350 a is further disposed between the plurality of secondportions 350 b adjacent to each other, the adjacent organic emissionlayers 370 may be provided not to be overlapped with each other, therebypreventing the color mixing phenomenon.

Next, the display device according to an exemplary embodiment will bedescribed with reference to FIGS. 13 to 17.

The display device according to the exemplary embodiment shown in FIGS.13 to 17 is substantially the same as the display device according to anexemplary embodiment shown in FIGS. 1 and 2 such that the descriptionthereof is omitted. In the illustrated exemplary embodiment, a pointthat seven transistors are included in one pixel is different from theprevious exemplary embodiment, and this is described in detail. However,a number of transistor sand capacitors included in one pixel may bevariously changed, and an arrangement shape of the transistor sand thecapacitors may be variously changed.

FIG. 13 is an equivalent circuit diagram of one pixel of a displaydevice according to an exemplary embodiment, FIG. 14 is a schematic planview of a transistor and a capacitor of a red pixel, a green pixel, anda blue pixel of a display device according to an exemplary embodiment,and FIG. 15 is a detailed plan view of one pixel of FIG. 14. FIG. 16 isa cross-sectional view of the display device of FIG. 15 taken along lineXVI-XVI, and FIG. 17 is a cross-sectional view of the display device ofFIG. 15 taken along lines XVII-XVII and XVII′-XVII′.

As shown in FIG. 13, the organic light emitting diode display accordingto an exemplary embodiment includes a plurality of signal lines 151,152, 153, 158, 171, 172, and 192, and a plurality of pixels PX connectedto the plurality of signal lines and arranged as a substantially matrixtype.

Each pixel PX includes a plurality of transistors T1, T2, T3, T4, T5,T6, and T7 respectively connected to the plurality of signal lines 151,152, 153, 158, 171, 172, and 192, a storage capacitor Cst, and anorganic light emitting diode OLED.

The transistors T1, T2, T3, T4, T5, T6, and T7 include a drivingtransistor T1, a switching transistor T2, a compensation transistor T3,an initialization transistor T4, an operation control transistor T5, alight emission control transistor T6, and a bypass transistor T7.

The signal lines 151, 152, 153, 158, 171, 172, and 192 include a scanline 151 transferring a scan signal Sn, a previous scan line 152transferring a previous scan signal S(n−1) to the initializationtransistor T4, a light emission control line 153 transferring a lightemission control signal EM to the operation control transistor T5 andthe light emission control transistor T6, a bypass control line 158transferring a bypass signal BP to the bypass transistor T7, a data line171 crossing the scan line 151 and transferring a data signal Dm, adriving voltage line 172 transferring a driving voltage ELVDD andprovided to be substantially parallel with the data line 171, and aninitialization voltage line 192 transferring an initialization voltageVint initializing the driving transistor T1.

A gate electrode G1 of the driving transistor T1 is connected to one endCst1 of the storage capacitor Cst, a source electrode S1 of the drivingtransistor T1 is connected with the driving voltage line 172 via theoperation control transistor T5, and a drain electrode D1 of the drivingtransistor T1 is electrically connected with an anode of the organiclight emitting diode OLED via the emission control transistor T6. Thedriving transistor T1 receives the data signal Dm according to aswitching operation of the switching transistor T2 to supply a drivingcurrent I_(d) to the organic light emitting diode OLED. An OLED currentI_(oled) flowing into the organic light emitting diode OLED may bederived by subtracting a bypass current I_(bp) flowing into the sourceelectrode S7 of the bypass transistor T7 from the driving current I_(d).

A gate electrode G2 of the switching transistor T2 is connected with thescan line 121, a source electrode S2 of the switching transistor T2 isconnected with the data line 171, and a drain electrode D2 of theswitching transistor T2 is connected with the source electrode S1 of thedriving transistor T1 and connected with the driving voltage line 172via the operation control transistor T5. The switching transistor T2 isturned on according to the scan signal Sn received through the scan line121 to perform a switching operation transferring the data signal Dmtransferred to the data line 171 to the source electrode S1 of thedriving transistor T1.

A gate electrode G3 of the compensation transistor T3 is directlyconnected with the scan line 121, a source electrode S3 of thecompensation transistor T3 is connected to the drain electrode D1 of thedriving transistor T1 and connected with an anode of the organic lightemitting diode OLED via the emission control transistor T6, and a drainelectrode D3 of the compensation transistor T3 is connected with one endCst1 of the storage capacitor Cst and the drain electrode D4 of theinitialization transistor T4 together with the gate electrode G1 of thedriving transistor T1. The compensation transistor T3 is turned onaccording to the scan signal Sn received through the scan line 121 toconnect the gate electrode G1 and the drain electrode D1 of the drivingtransistor T1, thereby diode-connecting the driving transistor T1.

A gate electrode G4 of the initialization transistor T4 is connectedwith a previous scan line 152, a source electrode S4 of theinitialization transistor T4 is connected with the initializationvoltage line 192, and a drain electrode D4 of the initializationtransistor T4 is connected with one end Cst1 of the storage capacitorCst, the drain electrode D3 of the compensation transistor T3, and thegate electrode G1 of the driving transistor T1. The initializationtransistor T4 is turned on according to the previous scan signal S(n−1)received through the previous scan line 152 to transfer theinitialization voltage Vint to the gate electrode G1 of the drivingtransistor T1, and then perform an initialization operation ofinitializing a voltage of the gate electrode G1 of the drivingtransistor T1.

A gate electrode G5 of the operation control transistor T5 is connectedwith the light emission control line 153, a source electrode S5 of theoperation control transistor T5 is connected with the driving voltageline 172, and a drain electrode D5 of the operation control transistorT5 is connected with the source electrode S1 of the driving transistorT1 and the drain electrode D2 of the switching transistor T2.

A gate electrode G6 of the emission control transistor T6 is connectedwith the light emission control line 153, a source electrode S6 of theemission control transistor T6 is connected with the drain electrode D1of the driving transistor T1 and the source electrode S3 of thecompensation transistor T3, and a drain electrode D6 of the emissioncontrol transistor T6 is electrically connected with an anode of theorganic light emitting diode OLED. The operation control transistor T5and the first emission control transistor T6 are simultaneously turnedon according to the emission control signal EM transmitted to the lightemission control line 153 such that the driving voltage ELVDD iscompensated through the diode-connected driving transistor T1 and istransmitted to the organic light emitting diode OLED.

A gate electrode G7 of the thin film bypass transistor T7 is connectedto the bypass control line 158, a source electrode S7 of the bypasstransistor T7 is connected to the drain electrode D6 of the lightemission control transistor T6 and the anode of the organic lightemitting diode OLED together, and a drain electrode D7 of the bypasstransistor T7 is connected to the initialization voltage line 192 andthe source electrode S4 of the initialization transistor T4. In thiscase, the previous scan line 152 is connected to the scan line 151transmitting the scan signal Sn in the previous pixel (not shown), andthe bypass control line 158 corresponds to the previous scan line 152such that the bypass signal BP is the same as the previous scan signalS(n−1).

The other end Cst2 of the storage capacitor Cst is connected with thedriving voltage line 172, and a cathode of the organic light emittingdiode OLED is connected with a common voltage line 741 transferring acommon voltage ELVSS.

As shown in FIGS. 14 and 15, the display device according to anexemplary embodiment includes a gate metal line 151, 152, 153, and 158including a scan line 151, a previous scan line 152, a light emissioncontrol line 153, and a bypass control line 158 respectively applying ascan signal Sn, a previous scan signal S(n−1), a light emission controlsignal EM, and a bypass signal BP, and provided in the row direction. Inthe exemplary embodiment, the bypass control line 158 is substantiallythe same as the previous scan line 152.

Also, a data metal line 171 and 172 includes a data line 171 and adriving voltage line 172 crossing the scan line 151, the previous scanline 152, the light emission control line 153, and the bypass controlline 158 and respectively applying a data signal Dm and a drivingvoltage ELVDD to the pixel PX. The initialization voltage Vint istransmitted from the initialization voltage line 192 to the compensationtransistor T3 through the initialization transistor T4. Theinitialization voltage line 192 is provided while alternately having astraight portion 192 a and an oblique portion 192 b. The straightportion 192 a is disposed to be parallel to the scan line 121, and theoblique portion 192 b extends at a predetermined angle with the straightportion 192 a.

Also, the pixel PX is provided with the driving transistor T1, theswitching transistor T2, the compensation transistor T3, theinitialization transistor T4, the operation control transistor T5, thelight emission control transistor T6, the bypass transistor T7, thestorage capacitor Cst, and the organic light emitting diode OLED. Thepixel PX shown in FIGS. 13 and 14 may correspond to the red pixel R, thegreen pixel G, and the blue pixel B forming the pentile matrixstructure.

The organic light emitting diode OLED includes the first electrode 191,the organic emission layer 370, and the second electrode 270. In thiscase, the compensation transistor T3 and the initialization transistorT4 may be provided as a transistor having a dual gate structure to cutoff a leakage current.

Each channel of the driving transistor T1, the switching transistor T2,the compensation transistor T3, the initialization transistor T4, theoperation control transistor T5, the light emission control transistorT6, and the bypass transistor T7 is provided inside one connectedsemiconductor 130 which may be bent in various shapes. In an exemplaryembodiment, the semiconductor 130 may include polysilicon or an oxidesemiconductor, for example.

The semiconductor 130 includes a channel which is doped with an N-typeimpurity or a P-type impurity, and a source doping part and a draindoping part which are provided at respective sides of the channel anddoped with an opposite-type doping impurity to the doping impurity dopedon the channel. In the exemplary embodiment, the source doping regionand the drain doping region correspond to the source electrode and thedrain electrode, respectively. The source electrode and the drainelectrode provided in the semiconductor 130 may be provided by dopingonly the corresponding regions. Further, in the semiconductor 130, aregion between source electrodes and drain electrodes of differenttransistors is doped, and thus the source electrode and the drainelectrode may be electrically connected to each other.

As illustrated in FIG. 15, the channel 131 includes a driving channel131 a provided in the drive transistor T1, a switching channel 131 bprovided in the switching transistor T2, a compensation channel 131 cprovided in the compensation transistor T3, an initialization channel131 d provided in the initialization transistor T4, an operation controlchannel 131 e provided in the operation control transistor T5, a lightemission control channel 131 f provided in the light emission controltransistor T6, and a bypass channel 131 g provided in the bypasstransistor T7.

The driving transistor T1 includes the driving channel 131 a, a drivinggate electrode 155 a, a driving source electrode 136 a, and a drivingdrain electrode 137 a. The driving channel 131 a may be curved, and mayhave a meandering shape or a zigzag shape. As such, by forming thecurved driving channel 131 a, the driving channel 131 a may be providedto be elongated in a narrow space. Accordingly, a driving range of thedriving gate-source voltage between the driving gate electrode 155 a andthe driving source electrode 136 a is increased by the elongated drivingchannel 131 a. Since the driving range of the gate voltage is increased,a grayscale of light emitted from the organic light emitting diode OLEDmay be finely controlled by changing the magnitude of the gate voltage,and as a result, the resolution of the organic light emitting diodedisplay device may be enhanced and display quality may be improved.Various examples such as ‘reverse S’, ‘S’, ‘M’, and ‘W’ may beimplemented by variously modifying the shape of the driving channel 131a.

The driving gate electrode 155 a overlaps with the driving channel 131a, and the driving source electrode 136 a and the driving drainelectrode 137 a are provided at respective sides of the driving channel131 a to be close. The driving gate electrode 155 a is connected to adriving connecting member 174 through a driving contact hole 61. Thedriving gate electrode 155 a corresponds to the gate metal line, and thedriving connecting member 174 corresponds to the data metal line.

The switching transistor T2 includes the switching channel 131 b, aswitching gate electrode 155 b, a switching source electrode 136 b, anda switching drain electrode 137 b. The switching gate electrode 155 bwhich is part of the portion extending downward from the scan line 151overlaps the switching channel 131 b, and the switching source electrode136 b and the switching drain electrode 137 b are provided at respectivesides of the switching channel 131 b, while being adjacent to eachother. The switching source electrode 136 b is connected to the dataline 171 through a switching contact hole 62.

The compensation transistor T3 includes the compensation channel 131 c,a compensation gate electrode 155 c, a compensation source electrode 136c, and a compensation drain electrode 137 c. The compensation gateelectrode 155 c that is a part of the scan line 151 is provided as twoto prevent a leakage current, and overlaps the compensation channel 131c. The compensation source electrode 136 c and the compensation drainelectrode 137 c are provided to be adjacent to respective sides of thecompensation channel 131 c. The compensation drain electrode 137 c isconnected to the driving connecting member 174 through a compensationcontact hole 63.

The initialization transistor T4 includes the initialization channel 131d, an initialization gate electrode 155 d, an initialization sourceelectrode 136 d, and an initialization drain electrode 137 d. Theinitialization gate electrode 155 d that is a part of the previous scanline 152 is provided as two to prevent the leakage current, and overlapsthe initialization channel 131 d. The initialization source electrode136 d and the initialization drain electrode 137 d are provided to beadjacent to respective sides of the initialization channel 131 d. Theinitialization source electrode 136 d is connected to an initializationconnecting member 177 through an initialization contact hole 64.

The operation control transistor T5 includes the operation controlchannel 131 e, an operation control gate electrode 155 e, an operationcontrol source electrode 136 e, and an operation control drain electrode137 e. The operation control gate electrode 155 e that is a part of thelight emission control line 153 overlaps the operation control channel131 e, and the operation control source electrode 136 e and theoperation control drain electrode 137 e are provided to be adjacent torespective sides of the operation control channel 131 e. The operationcontrol source electrode 136 e is connected to a part of the drivingvoltage line 172 through an operation control contact hole 65.

The light emission control transistor T6 includes the light emissioncontrol channel 131 f, a light emission control gate electrode 155 f, alight emission control source electrode 136 f, and a light emissioncontrol drain electrode 137 f. The light emission control gate electrode155 f that is a part of the light emission control line 153 overlaps thelight emission control channel 131 f, and the light emission controlsource electrode 136 f and the light emission control drain electrode137 f are provided to be adjacent to respective sides of the lightemission control channel 131 f The light emission control drainelectrode 137 f is connected to a pixel connecting member 179 through alight emission control contact hole 66.

The bypass transistor T7 includes the bypass channel 131 g, a bypassgate electrode 155 g, a bypass source electrode 136 g, and a bypassdrain electrode 137 g. The bypass gate electrode 155 g that is a part ofthe bypass control line 158 overlaps the bypass channel 131 g, and thebypass source electrode 136 g and the bypass drain electrode 137 g areprovided to be adjacent to respective sides of the bypass channel 131 g.

The bypass source electrode 136 g is connected directly to the lightemission control drain electrode 137 f, and the bypass drain electrode137 g is connected directly to the initialization source electrode 136d.

One end of the driving channel 131 a of the driving transistor T1 isconnected to the switching drain electrode 137 b and the operationcontrol drain electrode 137 e, and the other end of the driving channel131 a is connected to the compensation source electrode 136 c and thelight emission control source electrode 136 f.

The storage capacitor Cst includes a first storage electrode 155 a and asecond storage electrode 156 via a second gate insulating layer 142interposed therebetween. The first storage electrode 155 a correspondsto the driving gate electrode 155 a, and the second storage electrode156 as the portion extended from a storage line 157 has the wider areathan the driving gate electrode 155 a and covers the entire driving gateelectrode 155 a.

Here, the second gate insulating layer 142 includes a dielectricmaterial, and storage capacitance is determined by a charge charged inthe storage capacitor Cst and a voltage between both electrodes 155 aand 156. As such, the driving gate electrode 155 a is used as the firststorage electrode 155 a, and thus a space in which the storage capacitormay be provided may be secured in a space that is narrowed due to thedriving channel 131 a occupying a large area within the pixel.

The first storage electrode 155 a which is the driving gate electrode155 a is connected to one end of the driving connecting member 174through the driving contact hole 61 and a storage opening 51. Thestorage opening 51 is an opening which is provided in the second storageelectrode 156. Accordingly, the driving contact hole 61 to connect oneend of the driving connecting member 174 and the driving gate electrode155 a is provided inside the storage opening 51. The driving connectingmember 174 is provided with the same layer as the data line 171 to besubstantially parallel therewith, and the other end of the drivingconnecting member 174 is connected to the compensation drain electrode137 c of the compensation transistor T3 and the initialization drainelectrode 137 d of the initialization transistor T4 through thecompensation contact hole 63. Accordingly, the driving connecting member174 connects the driving gate electrode 155 a and the compensation drainelectrode 137 c of the compensation transistor T3 and the initializationdrain electrode 137 d of the initialization transistor T4 to each other.

The second storage electrode 156 is connected to the driving voltageline 172 through a contact hole 69.

Accordingly, the storage capacitor Cst stores storage capacitancecorresponding to a difference between the driving voltage ELVDDtransmitted to the second storage electrode 156 through the drivingvoltage line 172 and the gate voltage Vg of the driving gate electrode155 a.

The pixel connecting member 179 is connected to the pixel electrode 191through a contact hole 81, and the initialization connecting member 177is connected to the initialization voltage line 192 through a contacthole 82.

Hereinafter, the cross-sectional structures of the display deviceaccording to an exemplary embodiment will be described in detailaccording to a stacking order with reference to FIGS. 16 and 17.

In this case, since the stacked structures of the operation controltransistor T5 is substantially the same as that of the light emissioncontrol transistor T6, a detailed description thereof will be omitted.

A buffer layer 120 may be disposed on an insulating substrate 110.

A semiconductor 130 including a channel 131 including a driving channel131 a, a switching channel 131 b, a compensation channel 131 c, aninitialization channel 131 d, an operation control channel 131 e, alight emission control channel 131 f, and a bypass channel 131 g isdisposed on the buffer layer 120. A driving source electrode 136 a and adriving drain electrode 137 a are disposed on respective sides of thedriving channel 131 a in the semiconductor 130, and a switching sourceelectrode 136 b and a switching drain electrode 137 b are disposed onrespective sides of the switching channel 131 b. The compensation sourceelectrode 136 c and the compensation drain electrode 137 c are providedat both sides of the compensation channel 131 c, and the initializationsource electrode 136 d and the initialization drain electrode 137 d areprovided at both sides of the initialization channel 131 d. Theoperation control source electrode 136 e and the operation control drainelectrode 137 e are provided at both sides of the operation controlchannel 131 e, and the emission control source electrode 136 f and theemission control drain electrode 137 f are provided at both sides of theemission control channel 131 f The bypass source electrode 136 g and thebypass drain electrode 137 g are provided at respective sides of thebypass channel 131 g.

A first gate insulating layer 141 covering the semiconductor 130 isprovided thereon. On the first gate insulating layer 141, a first gatemetal line (151, 152, 153, 158, and 155 a) including the switching gateelectrode 155 b, the scan line 151 including the compensation gateelectrode 155 c, the previous scan line 152 including the initializationgate electrode 155 d, the light emission control line 153 including theoperation control gate electrode 155 e and the light emission controlgate electrode 155 f, the bypass control line 158 including the bypassgate electrode 155 g, and the driving gate electrode (the first storageelectrode) 155 a is provided.

The second gate insulating layer 142 covering the first gate metal line(151, 152, 153, 158, and 155 a) and the first gate insulating layer 141is disposed thereon. In an exemplary embodiment, the first gateinsulating layer 141 and the second gate insulating layer 142 mayinclude a silicon nitride (SiNx) or a silicon oxide (SiOx), for example.

On the second gate insulating layer 142, a second gate metal line (157and 156) including a storage line 157 parallel to the scan line 151 andthe storage electrode 156 as an expansion of the storage line 157 isprovided.

The second storage electrode 156 is wider than the first storageelectrode 155 a functioning as the driving gate electrode such that thesecond storage electrode 156 completely covers the driving gateelectrode 155 a.

A gate metal line 151, 152, 153, 155 a, 156, and 157 including the firstgate metal line (151, 152, 153, and 155 a) and the second gate metalline (156 and 157) may be provided as a multilayer in which metal layersincluding at least one of copper (Cu), a copper alloy, aluminum (Al), analuminum alloy, molybdenum (Mo), and a molybdenum alloy are stacked.

An interlayer insulating layer 160 is disposed on the second gateinsulating layer 142 and the second gate wires 157 and 156. Theinterlayer insulating layer 160 may include a silicon nitride (SiNx) ora silicon oxide (SiOx).

Contact holes 61, 62, 63, 64, 65, 66, and 69 are defined in theinterlayer insulating layer 160. On the interlayer insulating layer 160,a data metal line 171, 172, 174, 177, and 179 including a data line 171,a driving voltage line 172, a driving connecting member 174, aninitialization connecting member 177, and a pixel connecting member 179is provided. The data metal line (171, 172, 174, 177, and 179) may beprovided as a multilayer in which metal layers including at least one ofcopper (Cu), a copper alloy, aluminum (Al), an aluminum alloy,molybdenum (Mo), and a molybdenum alloy are stacked, and for example,may be provided as a triple layer of titanium/aluminum/titanium(Ti/Al/Ti), a triple layer of molybdenum/aluminum/molybdenum (Mo/Al/Mo),or a triple layer of molybdenum/copper/molybdenum (Mo/Cu/Mo).

The data line 171 is connected to the switching source electrode 136 bthrough the switching contact hole 62 defined in the first gateinsulating layer 141, the second gate insulating layer 142, and theinterlayer insulating layer 160, one end of the driving connectingmember 174 is connected to the first storage electrode 155 a through thedriving contact hole 61 defined in the second gate insulating layer 142and the interlayer insulating layer 160, and the other end of thedriving connecting member 174 is connected to the compensation drainelectrode 137 c and the initialization drain electrode 137 d through thecompensation contact hole 63 defined in the first gate insulating layer141, the second gate insulating layer 142, and the interlayer insulatinglayer 160.

The initialization connecting member 177 parallel to the data line 171is connected to the initialization source electrode 136 d through theinitialization contact hole 64 defined in the first gate insulatinglayer 141, the second gate insulating layer 142, and the interlayerinsulating layer 160. Also, the pixel connecting member 179 is connectedto the light emission control drain electrode 137 f through the lightemission control contact hole 66 defined in the first gate insulatinglayer 141, the second gate insulating layer 142, and the interlayerinsulating layer 160.

A passivation layer 180 covering the data metal line 171, 172, 174, 177,and 179 and the interlayer insulating layer 160 is disposed thereon. Thepassivation layer 180 covers the data metal line (171, 172, 174, 177,and 179) to be flattened such that the pixel electrode 191 may bedisposed on the passivation layer 180 without a step. In an exemplaryembodiment, the passivation layer 180 may include a stacked layer of anorganic material such as a polyacrylate resin, a polyimide resin, or thelike, or a stacked layer of an organic material and an inorganicmaterial.

The first electrode 191 and the initialization voltage line 192 aredisposed on the passivation layer 180. The pixel connecting member 179is connected to the first electrode 191 through the contact hole 81provided in the passivation layer 180, and the initialization connectingmember 177 is connected to the initialization voltage line 192 throughthe contact hole 82 provided in the passivation layer 180.

A pixel definition layer (“PDL”) 350 covering the passivation layer 180,the initialization voltage line 192, and the first electrode 191 isdisposed thereon. The pixel definition layer 350 includes a firstportion 350 a, and a second portion 350 b, and a pixel opening 351 isdefined in the pixel definition layer 350. The second portion 350 b ofthe pixel definition layer 350 has a thickness less than that of thefirst portion 350 a.

The organic emission layer 370 is disposed on the first electrode 191,and the second electrode 270 is disposed on the organic emission layer370. The second electrode 270 is also disposed on the pixel definitionlayer 350 over the plurality of pixels PX. As such, the organic lightemitting diode OLED including the first electrode 191, the organicemission layer 370, and the second electrode 270 is disposed.

The first electrode 191 includes the first portion 191 a overlapping thefirst portion 350 a of the pixel definition layer 350, the secondportion 191 b overlapping the second portion 350 b of the pixeldefinition layer 350, and the third portion 191 c overlapping the pixelopening 351 of the pixel definition layer 350. Here, the overlappingmeans to be overlapped in a vertical direction in a cross-sectionalview.

The second electrode 270 includes the first portion 270 a overlappingthe first portion 350 a of the pixel definition layer 350, the secondportion 270 b overlapping the second portion 350 b of the pixeldefinition layer 350, and the third portion 270 c overlapping the pixelopening 351 of the pixel definition layer 350.

Accordingly, the first electrode 191 and the second electrode 270overlap the first portion 350 a, the second portion 350 b, and the pixelopening 351 of the pixel definition layer 350.

The third portion 191 c of the first electrode 191 positioned in thepixel opening 351 and the third portion 270 c of the second electrode270 are in contact with the organic emission layer 370. The pixelopening 351 defines a light emission region.

It is shown that the organic emission layer 370 overlaps the secondportion 350 b of the pixel definition layer 350, but the organicemission layer 370 may not overlap the second portion 350 b of the pixeldefinition layer 350 as described above.

In the illustrated exemplary embodiment, when the thickness of thepartial region of the pixel definition layer 350 decreases and the firstelectrode 191 and the second electrode 270 are overlapped in thecorresponding region, the capacitance may be additionally secured.

An encapsulation member (not shown) protecting the organic lightemitting diode OLED may be disposed on the second electrode 270, and theencapsulation member may be sealed to the substrate 100 by a sealant andmay include various materials such as glass, quartz, ceramic, plastic,and a metal. A thin film encapsulation layer may be disposed on thecommon electrode 270 by depositing the inorganic layer and the organiclayer with the usage of the sealant.

The display device according to an exemplary embodiment will bedescribed with reference to FIG. 18.

The display device according to the exemplary embodiment shown in FIG.18 is substantially the same as the display device according to anexemplary embodiment shown in FIGS. 13 to 17 such that the descriptionthereof is omitted. In the illustrated exemplary embodiment, the planeshape of the first electrode is different from the previous exemplaryembodiment, and this is described in detail.

FIG. 18 is a plan view of a display device according to an exemplaryembodiment.

Like the previous exemplary embodiment, the display device according tothe illustrated exemplary embodiment includes seven transistors, thefirst electrode 191, the organic emission layer 370, and the secondelectrode.

The plane shape of the first electrode 191 and the organic emissionlayer 370 is different from the previous exemplary embodiment, and theplane shape of the first electrode 191 and the organic emission layer370 may be designed to be variously changed as described above. Also, itis shown that the organic emission layer 370 and the first electrode 191are completely overlapped, but the invention is not limited thereto, andthe organic emission layer 370 and the first electrode 191 may beoverlapped at a partial region. Further, the organic emission layer 370may be positioned only in the pixel opening 351. Like the previousexemplary embodiments, as the second portion 350 b of the pixeldefinition layer 350 is thinner than the first portion 350 a and thesecond portion 350 b overlaps the first electrode 191 and the secondelectrode 270, the capacitance may be additionally secured, therebyimproving the reliability of the element.

A plurality of pixels R, G, and B may be disposed as the pentile type,and the first electrode 191 of the red pixel R may be larger than thefirst electrode 191 positioned in the green pixel G. Also, the firstelectrode 191 positioned in the blue pixel B may be larger than thefirst electrode 191 positioned in the green pixel G. The first electrode191 positioned in the red pixel R and the first electrode 191 positionedin the blue pixel B may be symmetric.

While this invention has been described in connection with what ispresently considered to be practical exemplary embodiments, it is to beunderstood that the invention is not limited to the disclosedembodiments, but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

What is claimed is:
 1. A method for manufacturing a display device, themethod comprising: forming a first electrode on a substrate; forming anorganic material layer on the substrate and the first electrode;patterning the organic material layer to form a pixel definition layerincluding a first portion, a second portion, and a pixel opening;forming an organic emission layer on the first electrode; and forming asecond electrode on the organic emission layer, wherein the secondportion has a thickness less than that of the first portion, and thesecond portion overlaps the first electrode and the second electrode. 2.The method of claim 1, wherein at least one of a slit mask and ahalf-tone mask is used in the patterning the organic material layer. 3.The method of claim 1, wherein the pixel opening is enclosed by thefirst portion.
 4. The method of claim 1, wherein the first electrode andthe second electrode overlap the first portion, the second portion, andthe pixel opening of the pixel definition layer.
 5. The method of claim4, wherein a distance between a first portion of the first electrodeoverlapping the first portion of the pixel definition layer and a firstportion of the second electrode is greater than a distance between asecond portion of the first electrode overlapping the second portion ofthe pixel definition layer and a second portion of the second electrode.6. The method of claim 1, wherein the first portion of the pixeldefinition layer is positioned between the pixel opening and the secondportion.
 7. The method of claim 1, wherein the second portion of thepixel definition layer further overlaps the organic emission layer.